Warning: the pictures could be from Antarctica, after all, and it is not even clear whether supercooling was the only cause.Michigan has had the coldest winter in decades. Water expands to freeze, and at Mackinaw City the water in Lake Huron below the surface ice was super-cooled.
It expanded to break through the surface ice and froze instantly into this incredible wave. Isn't it beautiful?
Hat tip: Fred Moss and Jiří Wagner